mysql, the same table modifies one of the two fields based on two of the fields

Question

There is a student table with table fields including id, name, parent_id, createDate, etc. Now we need to modify the names of students with the same name under the same parent_id based on parent_id, name, to ensure that they no longer exist under the same parent_id. How to deal with duplicate names

Answer 1

select * 
  from student 
  where id not in(select min(id) from student group by parent_id,name)t

This is to find duplicate students. As for how to modify it, it’s up to you.

Supplement:
The modification is to sort according to createDate, and then add the sorted serial number after the name

update student t1 inner join 
    (select idx,id 
     from
         (select if(@m_last_parent_id=parent_id and @m_last_name=name,@m_i:=@m_i+1,@m_i:=0) idx,
             @m_last_parent_id:=parent_id,@m_last_name:=name,id,parent_id,name,createDate 
          from student
          order by parent_id,name,createDate
         )m 
     where idx>0
    )t2 on t1.id=t2.id 
set t1.name=concat(t1.name,t2.idx);

This is the result of my own test: